When roads are built, it is usually to service a particular land-use such as housing, factories or farms. However, land-use can change over time. When roads are used for a purpose that they were not built for, they can become inefficient and dangerous. Even planned land uses, such as commercial activity, can outgrow a site and spread onto adjacent land, including road space.

Stalls and street traders can cause safety problems if they are too close to the road. Unauthorised vehicle access between major roads and sellers can lead to crashes between vehicles turning into or out of the commercial activity area and through traffic. Pedestrian crashes can also be a problem near such developments.

Individual sellers should be educated, and encouraged to set up their stalls at places where vehicles can safely pull off the road, and planners and engineers should consider building a lay-by for this purpose. Strict enforcement may also be required to prevent stalls being built too close to the road. Illegally placed stalls which create unsafe traffic conditions should be removed as soon as possible, and the site should be monitored so they are not rebuilt.

Where roadside commercial activities cannot be relocated, adequate traffic calming schemes should be formulated to alert drivers and to reduce their speed approaching and passing through the road section.